JPS6231169B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine in which the walls of the auxiliary combustion chamber can be maintained at an elevated temperature level by avoiding heat release to the cooled parts of the engine. Such devices are known in particular for secondary combustion chambers in stratified internal combustion engines. Such an auxiliary combustion chamber is constructed in the auxiliary combustion chamber body as an approximately cup-shaped insert with thin walls, which in the cold state is spaced apart from the cylinder head wall to be cooled. , forming a gap between the wall and the wall;
Therefore, it has an insulating effect, and in the heated state, due to the expansion of the insert material, it comes into contact with the cylinder head wall to be cooled, thereby causing a heat release that avoids a temperature increase.

According to new knowledge, the carbon and hydrocarbon emissions are very significantly reduced by the walls of the sub-combustion chamber, which are kept at a very high temperature, into which the fuel is injected. However, the known devices have a very high thermal inertia and require a relatively long time after start-up to reach the wall temperature required for a good mixture formation. Furthermore, the known device is subject to relatively large temperature fluctuations during internal combustion engine operation. This is because temperature control of the auxiliary combustion chamber wall surface can only be achieved incompletely due to thermal inertia. Particularly if the internal combustion engine output changes rapidly, this auxiliary combustion chamber wall will become excessively heated.

In addition, in the cold state, the cylinder head wall to be cooled and the insert body wall are formed between the cylinder head wall and the insert body wall.
Carbon and other combustion residues inevitably enter the adiabatic gaps, and the desired effect ceases to occur as the engine is operated.

In contrast, the configuration of the present invention having the features described in the claims provides the following advantages.
This means that the heating of the auxiliary combustion chamber walls takes place very early after the engine is started, due to the very good thermal insulation of the heating element to the cooled parts of the internal combustion engine, and that the desired high temperature is It holds up satisfactorily even under different operating conditions. This is because in this case a rapid control of the amount of heat to be transferred is possible due to the very good thermal conductivity due to the vaporization and condensation of the internal filling of lithium, sodium, etc. in the heating body.

The invention will now be explained with reference to the illustrated embodiment.

The drawing shows the structure of an embodiment of a sub-combustion chamber body 20 in a cylinder head 2 of an internal combustion engine. The auxiliary combustion chamber body 20 has in this case a spherical auxiliary combustion chamber 21 in a known manner, in which the injection valve 11 is arranged on one side and an overflow channel 24 on the opposite side. The main combustion chamber of the internal combustion engine is connected via the Furthermore, a preheating plug 17 penetrates into the auxiliary combustion chamber 21 in a conventional manner.

In the illustrated embodiment, the temperature-controlled sub-combustion chamber wall 14 of the spherical sub-combustion chamber 21 is constructed as a partition wall of one or more hollow heating bodies 13 . Furthermore, in the lower 1/3 of the spherical sub-combustion chamber 21, there is a heating element 2 which is hollow in a direction transverse to the direction of the fuel injection flow.
2 is provided, which itself is constructed as a heating tube. This heating element 22 passes through the wall of the auxiliary combustion chamber and is in thermally conductive contact with the cylinder head wall 7 to be cooled. There is a temperature value in the heating element 22 and the heating element 13 at which heat conduction (radiation) of the auxiliary combustion chamber wall by the heating element 22 and the heating element 13 to the cylinder head wall 7 to be cooled is performed. , and is customarily partially filled with lithium or sodium, depending in each case on the temperature level at which the temperature of the auxiliary combustion chamber walls to be controlled is to be maintained. During starting of the internal combustion engine, the heating elements 22 and 13 serve to thermally insulate the auxiliary combustion chamber wall from the cooled cylinder head wall 7 of the cylinder head 2. The walls of the auxiliary combustion chamber are therefore rapidly heated and quickly reach a temperature at which the fuel injected into the auxiliary combustion chamber 21 can vaporize satisfactorily. Also, excessive heating of the sub-combustion chamber wall can be caused by heating element 2.
This is avoided by the particularly good thermal conductivity of heating element 2 and heating element 13. The heating element 22 and the heating element 13 also react very quickly to temperature changes resulting from load changes of the internal combustion engine.

[Brief explanation of the drawing]

The drawing shows an embodiment of the present invention in a sub-combustion chamber of an internal combustion engine. 2... Cylinder head, 7... Cylinder head wall, 9... Cooling chamber, 11... Injection valve, 13... Warming body, 14... Sub-combustion chamber wall, 17... Preheating plug, 2
0...Sub-combustion chamber body, 21...Sub-combustion chamber, 22...
Heating element, 24...overflow passage.

Claims (1)

[Claims] 1 In an internal combustion engine in which the walls of the auxiliary combustion chamber can be maintained at an elevated temperature level by avoiding heat release to the cooled parts of the engine, the auxiliary combustion chamber 21
A heating body 22 is arranged in a direction transverse to the direction of the fuel injection flow into the sub-combustion chamber 21, and the heating body 22 is configured as a heating tube, and inside thereof,
A filling such as lithium or sodium is enclosed, and both ends of the heating body 22 are in thermally conductive contact with the cooled part 7 of the internal combustion engine as internal filling condensation which releases heat. An internal combustion engine characterized by: